Introduction:

We use levers because of a Force-Distance Tradeoff. If you want to increase your output FORCE, you must increase you input DISTANCE. Wheel/Axles and Screws also work this way.

Activity:

Try the wheel/axle and screw samples provided by your teacher. Then measure the input and output distances using string.

DIAGRAM/EXPLANATION
How is a screw like a lever?
OR
How is a wheel and axle like a lever?
OR
The Archimedean Screw used rotational action to move water up a pipe. Why didn't they just lift it directly?
OR
"In the financial news, I keep hearing about "leveraged buyouts", but I don't know what they mean. Maybe you can help by explaining the concept of leverage. Help!"

Use the concepts of FORCE-DISTANCE TRADEOFF in your answers!

Conclusion:

When you know the input and output distances, you can calculate a machine's Mechanical Advantage!

Enrichment: